关于createfile的问题?

Question

public readdriver(string driverName)
{
Load(driverName);
}
public void Load(string driverName)
{
if (driverName == null && driverName.Length == 0)
{
throw new ArgumentNullException("driverName");
}

handleValue = CreateFile("\\\\.\\"+driverName, GENERIC_READ|GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_READ,IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero);
if (handleValue.IsInvalid)
{
Marshal.ThrowExceptionForHR(Marshal.GetLastWin32Error());
}
}
请大家看一下，问什么在读取光驱时很正常，在读取硬盘时就不成功呢？
按你这么说，那光盘也不应该读取出来，这是api编程，还有，createfile也可以打开文件的好不